fix timestamp sign problem

bundler/src/main/java/io/ib67/sfcraft/bundler/BundleReader.java

@@ -85,7 +85,18 @@ public class BundleReader {
                             var result = reassembler.writeReassembled(RegionFile.CompressType.ZLIB);
                             try (var fc = FileChannel.open(path, StandardOpenOption.CREATE,
                                     StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING)) {
-                                result.readBytes(fc, 0, result.readableBytes());
+                                // readBytes(FileChannel, ...) does a single channel write and
+                                // may write fewer bytes than requested; loop or the region file
+                                // is silently truncated.
+                                long pos = 0;
+                                int remaining = result.readableBytes();
+                                while (remaining > 0) {
+                                    int written = result.readBytes(fc, pos, remaining);
+                                    if (written <= 0)
+                                        throw new IOException("Short write restoring " + entry.name() + " to " + path);
+                                    pos += written;
+                                    remaining -= written;
+                                }
                             } finally {
                                 result.release();
                             }

bundler/src/main/java/io/ib67/sfcraft/bundler/EntryInputStream.java

@@ -25,8 +25,12 @@ public class EntryInputStream extends FilterInputStream {
     public BundleEntry readEntry() throws IOException {
         var magic = (short) (in.read() << 8 | in.read()); // u16
         if (magic != BundleEntry.MAGIC) throw new IOException("Invalid magic number: "+Long.toHexString(magic));
+        // every byte must be widened to long before shifting: an int shift such as
+        // `in.read() << 24` goes negative when the byte is >= 0x80 and sign-extends into the
+        // high 32 bits, corrupting the timestamp (which then makes the entry look "too old"
+        // and get silently skipped on restore).
         var time = (long) in.read() << 56 | (long) in.read() << 48 | (long) in.read() << 40 | (long) in.read() << 32 |
-                (long) in.read() << 24 | in.read() << 16 | in.read() << 8 | in.read();
+                (long) in.read() << 24 | (long) in.read() << 16 | (long) in.read() << 8 | (long) in.read();
         var attribute = VarInts.readVarInt(in);
         var segmentLen = VarInts.readVarLong(in);
         var lenName = VarInts.readVarInt(in);

bundler/src/test/java/io/ib67/bundler/TestBundleReader.java

@@ -73,6 +73,26 @@ public class TestBundleReader {
                 "the symlink itself must be recreated at the link's path, not at its target");
     }
 
+    @Test
+    public void testTimestampWithHighBitSurvivesRoundTrip(@TempDir Path tmp) throws IOException {
+        // 1798761600000 has 0xCE at bits 24-31; an int shift on that byte sign-extends and
+        // makes the decoded time negative, which used to make extract() skip the entry as
+        // "too old". ~half of all real-world dates land in such a band.
+        var time = 1798761600000L;
+        assertTrue(((time >> 24) & 0xFF) >= 0x80, "test vector must exercise the sign-extension path");
+        var bundle = tmp.resolve("hibit.swb.zst");
+        var payload = "kept".getBytes();
+        try (var zstd = new ZstdOutputStreamNoFinalizer(Files.newOutputStream(bundle), 3);
+             var out = new EntryOutputStream(zstd)) {
+            out.writeEntryHeader("world.dat", (short) 0, payload.length, time);
+            out.write(payload);
+        }
+        var dest = tmp.resolve("dest");
+        BundleReader.builder().build().extract(bundle, dest);
+        assertEquals("kept", Files.readString(dest.resolve("world.dat")),
+                "entry must not be skipped just because its timestamp byte has the high bit set");
+    }
+
     @Test
     public void testTruncatedEntryThrowsInsteadOfLooping(@TempDir Path tmp) throws IOException {
         var bundle = tmp.resolve("truncated.swb.zst");